The 2013 Houston Astros were marking a new beginning for the franchise, playing their first season in the American League after spending their first 51 years in the National League. The team was also hoping to get off on a better foot, after setting a team record for losses in each of its last two seasons in the senior circuit. Rookie manager Bo Porter was at the helm, and saw the year start on the right foot when on March 31st the Astros recorded an 8-2 win over cross-state rivals the Texas Rangers in the opening game of the major league season. Bud Norris was credited with the win, Erik Bedard earned his first career save with 3 1/3 scoreless innings, Justin Maxwell became only the 6th player to hit a pair of triples on Opening Day, and Rick Ankiel pinch-hit a three-run homer in the 6th inning in the historic contest. The joy was short-lived, however, as in their second game, on April 2nd, the Astros came within one batter of being victims of a perfect game; Marwin Gonzalez managed a single up the middle with two outs in the 9th to deprive Yu Darvish of the achievement, but they still lost, 7-0. In their third game on April 3rd, they were shut out again by the Rangers, this time by Alexi Ogando. All three Ranger starters in the series - Matt Harrison, Darvish and Ogando - matched or set personal bests for strikeouts in their starts, and the Astros ended up setting a record for most Ks in an opening three-game series with 43, which many observers saw as a potential harbinger of serious trouble down the road. Indeed, the Astros went on a six-game losing streak, in which their offense was completely impotent.

Ironically, the Astros broke out of their offensive slump with one of the greatest hitting performance in team history on April 9th, when they banged out 22 hits, including 5 homers, in defeating the Seattle Mariners, 16-9. Bedard had his second excellent outing of the season on the mound, giving up no runs and leaving with a 13-0 lead after four innings in his first start, but it was reliever Paul Clemens who claimed the win in his big league debut, in spite of giving up up five runs and three homers in four innings of work. Chris Carter had the first two-homer game of his career in the win with his first two long balls of the season, and J.D. Martinez, Gonzalez and Jose Altuve all went deep for the first time of the year. In spite of such isolated highlights, the Astros got off to another very difficult start, as had been expected. After 19 games, they were only 5-14, their worst start since 1969, when the team began the year 4-20; that year, the Astros had managed to right the ship, finishing at .500, something that looked infinitely improbable this year. But for all their struggles, the Astros had still managed to outplay the Miami Marlins, who were 4-15 at that point and had a minus 46 run differential, making the Astros' minus 34 look perfectly reasonable in comparison.

The Astros played only slightly better in May than they had in April, finishing the month at 10-16, with a run differential of -47, after going 7-19, -51 in April (their big win on opening day, having come in March, made those numbers slightly less awful). They were already 16 1/2 games back of first place by the end of May. However, they had a rare winning streak at that point, reeling off six consecutive victories, all on the road, from May 29-June 3rd, including a four-game sweep of the Los Angeles Angels of Anaheim. It was the first time an Astros team had had a perfect road trip since 1999. They seemed to have turned a corner at that point, but ended June on a 3-7 mark after threatening to play .500 ball for the month, but finishing at 12-15. As the Marlins had also improved, they only had one more win than the Fish on June 30th and were still dead last in the AL.

The Astros continued to lose over the second half of the year. They passed 100 losses for the third straight season with a 10-0 loss to the Cincinnati Reds on September 17th, and continued to lose after that. On September 23rd, they suffered a 12-0 pasting at the hand of the Rangers that epitomized the way their season had gone: not only did Derek Holland pitch a complete game shutout, he also struck out 9 batters, consolidating the team's huge lead atop the majors' strikeout standings, but Alex Rios also hit for the cycle in only 6 innings, handing Houston its 106th loss of the year, one shy of the franchise record set the previous season. The day before, the telecast of their Sunday afternoon game against the Cleveland Indians drew an astonishing 0.0 Nielsen rating, meaning that none of the viewers being sampled in the Houston area that day had watched the game, which was in direct competition with an NFL game between the Houston Texans and the Baltimore Ravens. Loss number 107, tying the franchise record set the previous season, came at the hands of the Rangers on September 24th, the 11th straight loss by the Astros at that point. Loss number 12 in a row on September 25th, 7-3 to the Rangers, established a new franchise record for ineptitude. They finished the year by being swept at home by the New York Yankees, pushing their losing streak to 15 and their final record to 51-111. It was the most losses by any team since the 2003 Detroit Tigers had lost 119 games, and the 15 losses to end the season were a major league record (the streak was snapped when the Astros beat the Yankees on Opening Day in 2014). Houston's batters set a major league record by striking out 1,535 times during the season. Still, there was some hope for the team's fans, as their minor league system was loaded with prospects, as demonstrated by the fact that six of their minor league affiliates played in the postseason, demonstrating that help would soon be on the way.